Truss structure for beams



Jan. 9, 1968 VAN RADEN v 3,362,1 17

TRUSS STRUCTURE FOR BEAMS Filed May 24, 1965 HARVEY B. VAN RADEN/NVE/V7'0/? BY BUC/(HOR/V, BLORE, KLAROU/ST 8 SPAR/(MAN ATTORNEYS UnitedStates Patent Ofiice 3,362,117 Patented Jan. 9, 1968 3,362,117 TRUSSSTRUCTURE FOR BEAMS Harvey B. Van Raden, Rte. 3, Box 246, Hillsboro,Oreg. 97123 Filed May 24, 1965, Ser. No. 458,255 Claims. (Cl. 52225)ABSTRACT OF THE DISCLOSURE A beam or pair of rafters have bracketsmounted on their opposite ends connected by a tie rod, the bracketshaving portions to bear against the beam or rafters when a load isapplied to supply a reverse movement thereby to relieve to some extentthe tension resulting from the load.

The present invention relates to a truss structure for use with loadbearing rafters or beams and to apparatus for pretensioning suchstructures and for applying re action forces to such structures as toincrease their load carrying capabilities.

A particular object of the present invention is to provide anarrangement wherein the force of a load upon a beam or rafter is causedto apply a reverse moment to the portion of the beam which wouldotherwise be placed in tension thereby increasing the load carryingcapabilities of such beam or rafter.

Another object of the invention is to provide new and improved bracketsfor use with beams or rafters so as to aply a reverse movement to themupon the occasion of loading of the beam or rafter.

Other objects and advantages of the invention will be come more apparenthereinafter.

In accordance with an illustrated embodiment of the present invention,mounted to the opposite ends of a load bearing structure adapted to spanan area and having portions placed in tension by reason of a loadimposed on such structure are a pair of brackets mounted one adjacenteach end of the structure. Means are provided for pivotally mountingsaid brackets on said structure and the brackets are pivotally connectedby a tie rod which is placed in tension. The brackets are provided withmeans to engage the structure and to apply to said structure, by reasonof the tension of the tie rod, a moment opposite to that resulting froma load imposed on the structure.

For more details of the invention reference is made to the accompanyingdrawing wherein:

FIG. 1 illustrates a roof truss constructed in accordance with theinvention;

FIG. 2 is an end View of a bracket utilized in such roof truss made inaccordance with the invention;

FIG. 3 is a side elevation of the bracket;

FIG. 4 is an elevation of a beam construction made in accordance withthe invention; and

FIG. 5 is still another roof truss constructed in accordance with theinvention.

Referring first to FIGURE 1, there is therein shown the application ofthe invention to a roof truss comprising a pair of opposed raftersabutting each other at their upper ends at which they may be joined byany suitable means. The lower ends of the rafters may be suitablysupported on posts or uprights 12 which may comprise the sidewalls of abuilding. Mounted one on each of the rafters near the lower end thereofis a pair of brackets 14, details of the construction of which arebetter shown in FIGURES 2 and 3. Each of the brackets 14 comprises apair of side plates 16 that are disposed one on each of the oppositesides of a rafter 10. The side plates 16 are more or less triangular inshape and are joined at one of their apices by a tie bar 18 which isadapted to fit Within a notch 20 formed in the corresponding rafter. Thecooperative engagement of the notches 20 and tie bars 18 anchor thebrackets against movement longitudinally of the rafters and define, aswill become more apparent, a pivot point about which the brackets mayrotate. Between a forwardly extending pair of apices of the plates 16extends a second tie bar or pressure plate 22 which engages theunderside of the corresponding rafters 10.

Each pair of side plates is joined at the third apices thereof by athird plate 24 having an opening to receive the end of a tie rod 26 thatextends between the brackets, the ends of the tie rod being threaded toreceive nuts 28 that may be threaded onto the tie rod 26 to applytension thereto. When the tie rod 26 is under tension, the brackets 14rotate relatively about their tie bars 18 to cause the pressure plates22 to be forced against the under side of the rafters thereby applying areverse movement against the rafters and in effect pretensioning thesame and causing the same to camber. The under side of each of therafters 10 is thus placed in compression rather than tension, as wouldbe its normal condition, whereby, as will be readily apparent, theloadbearing capacity of the rafters 10 is materially increased.Computation will show that the load-bearing capacity of a member willincrease by as much as 30 percent by reason of the tension applied bymeans of the brackets 14 and tie rod 26.

As will be apparent the brackets 14 may assume various configurationsand the brackets may be pivotally secured to rafters and beams by manysuitable means. For example, if the rafters 10 are of steel the tie barsmay be welded to the upper surafce of the rafters or the brackets may besecured by bolts extending through the corresponding rafters as shown inFIGS. 4 and 5.

The application of the principles of the invention to a single beam 30is shown in FIGURE 4. The beam 30 is shown as a simple beam supported atits opposite ends by any suitable supports indicated at 32. Mounted oneadjacent each of the opposite ends of the beam 30 is a pair of brackets34, each comprising a pair of side plates 36 pivotally secured to thebeam by a bolt 38 extending through the beam and the side plates. Eachof the brackets 34 includes a pressure plate 39 extending between theside plates 36 beneath the under surface of the beam 30. Extendingbetween each of the brackets 34 is a tie rod 42 which may comprise apair of clevises 44 suitably secured to the brackets 36 beneath the beam30 whereby the tie rod 42 is displaced from the axis of the beam andfrom the plane extending through the axes of the pivot points 38. Thetie rod 42 is provided with a turn buckle 46 whereby the tie rod may betensioned to cause the pressure plates 39 to be forced upwardly againstthe lower surface of the beam 30 thereby causing the lower portion ofthe beam to be placed in compression. This again will effectivelyincrease the load bearing capacity of the beam 30.

Referring now to FIGURE 5 the combination of the application of theprinciples of the preceding embodiments to a truss structure is thereinshown. The embodiment of FIGURE 5 comprises a pair of rafters 40supported near their opposite ends on posts or walls 42. The upper endsof the rafters 40 oppose one another and are held against one another byany suitable means. Mounted on each of these rafters adjacent theopposite ends thereof are brackets 49, 50, each of which comprises apair of side plates embracing the opposite sides of the correspondingrafter 40. The brackets 49, 50 are each held in place for pivotalmovement about a horizontal axis by a bolt 52 extending through thecorresponding rafter. The brackets 49, 50 of each rafter are connectedby a tensioning tie rod 54, which upon tensioning is adapted to force apressure plate 56 of each bracket against the under surface of thecorresponding rafter, thereby placing the lower portion of each of therafters in compression. In addition, the lower brackets 50 on theopposed rafters are joined by a tensioning tie rod 58 that is adapted toapply additional pressure to the beams through the pressure plates 56 ofthe lower brackets, particularly when a load is applied to the rafters40. The load carrying capacity of the rafters 40 is thereby increased.

Having illustrated and described a preferred embodiment of the inventionit should become apparent to those skilled in the art that the inventionpermits of modification in arrangement and detail. I claim all suchmodifications as come within the spirit and scope of the appendedclaims.

I claim:

1. A truss structure comprising:

a pair of opposed rafters having abutting upper ends,

a pair of brackets mounted one on each of said rafters adjacent thelower ends thereof,

means pivotally securing said brackets to said rafters for pivotalmovement of each of said brackets about a given horizontal axisextending at right angles to the longitudinal axis of the rafter onwhich it is mounted and restraining said brackets from movementlongitudinally of said rafters,

a tie rod extending between said brackets, and

pressure plate means on each of said brackets engaging the under side ofthe rafter on which the bracket is mounted, said tie rod being intension whereby said pressure plate means are forcibly thrust againstcorresponding rafter.

2. A truss structure comprising:

a pair of opposed rafters having abutting upper ends,

a pair of brackets mounted one on each said rafters adjacent the lowerends thereof,

said brackets each comprising a pair of generally trianglar side platesdisposed one on each of the opposite sides of the corresponding rafters,

means pivotally mounting said brackets adjacent one corner thereof tosaid rafters for rotation about axis normal to the longitudinal axis ofthe rafters and restraining the brackets against movement longitudinally of the rafters, each of said brackets having a pressure plate fixedto and extending between said side plates thereof at a second apex ofsaid plates,

each said pressure plate extending beneath the corresponding rafter andbeing positioned relatively between said axis of rotation and the upperend of such rafter,

the third apices of said side plates extending beneath said rafters, and

a tie rod extending between and engaging said brackets at the thirdapices thereof,

said tie rod being in tension whereby said brackets are caused to pivotabout said axes and said pressure plates are forcefully pressed againstthe lower surfaces of said rafters to camber the same.

3. A truss structure comprising:

a pair of opopsed inclined rafters having abutting upper ends,

a pair of brackets mounted one on each said rafter adjacent the lowerends thereof,

said brackets each comprising a pair of generally triangular side platesdisposed one on each of the opposite sides of the corresponding rafters,

each of said brackets having a first tie bar fixed to and extendingbetween said side plates thereof at an apex of said plates,

means securing said first tie bars to the upper surface of said raftersand restraining the brackets against movement longitudinally of therafters, each of said brackets having a second tie bar fixed to andextending between said side plates thereof at a second apex of saidplates,

each said second tie bar extending beneath the corresponding rafter andbeing positioned relatively between said first tie bar and the upper endof such rafter,

the third apices of said plates extending beneath said rafters and beingpositioned between the second tie bars and the lower ends of saidrafters, and

a tie rod extending between and engaging said brackets at the thirdapices thereof,

said tie rod being in tension whereby said brackets are caused to pivotabout said first tie bars thereof and the second tie bars thereof areforcefully pressed against the lower surfaces of said rafters to camberthe same.

4. A truss structure comprising:

a pair of opposed inclined rafters having abutting upper ends,

a pair of brackets mounted one on each said rafters adjacent the lowerends thereof,

said brackets each comprising a pair of generally triangular side platesdisposed one on each of the opposite sides of the corresponding rafters,

each of said brackets having a first tie bar fixed to and extendingbetween said side plates thereof at an apex of said plates,

said rafters each having a notch in the upper surface thereofcooperatively receiving said first tie bar and restraining the bracketsagainst movement longitudinally of the rafters, each of said bracketshaving a second tie bar fixed to and extending between said side platesthereof at a second apex of said plates,

each said second tie bar extending beneath the corresponding rafter andbeing positioned realtively between said first tie bar and the upper endof such rafter,

the third apices of said side plates extending beneath said rafters andbeing positioned between the second tie bars and the lower ends of saidrafters, and

a tie rod extending between and engaging said brackets at the thirdapices thereof,

said tie rod being in tension whereby said brackets are caused to pivotabout said first tie bars thereof and the second tie bars thereof areforcefully pressed against the lower surfaces of said rafters to camberthe same.

5. A truss structure comprising:

a pair of opposed rafters having abutting upper ends,

a pair of brackets mounted on each of said rafters one adjacent each ofthe opposite ends thereof,

means for securing said brackets to said rafters to allow pivotalmovement of each of said brackets about a given horizontal axisextending at right angles to the longitudinal axis of the rafter onwhich it is mounted and restraining said brackets from movementlongitudinally of said rafters,

a tie rod connected to and extending between each of said pairs ofbrackets,

pressure plate means on each of said brackets engaging the under side ofthe rafter on which the bracket is mounted, said tie rods being intension whereby said pressure plate means are forcibly thrust againstcorresponding rafter, and

a further tie rod connected to and extending between the lowermostbracket on each of said rafters,

and means for placing said further tie rod in tension further to urgesaid pressure plate means against said 2,021,480 11/1935 Davidson 52-639X rafters. 2,793,720 5/1957 Hawes 52223 X References Cited FOREIGNPATENTS UNITED STATES PATENTS 248,638 1963 Australia.

457,418 8/1891 Hodges 52-90 5 1,090,405 3/1914 Morrison 52291 JOHN E.MURTAGH, Primary Examiner.

